Will my photos/videos be backed up if I update my iphone?

I remember having issues with iphones a couple years ago with this and can't remember if it did or not.

Go to your iCloud on your phone and all the way at the bottom it should be something about a backup, I will post a picture. But you're going to want to pick where it says to do a back up now. It will begin and tell you an estimated time of how long is left of backing up your phone. It will tell you when it's complete. When you set up your new iPhone you will want to choose to back up with iCloud account, you'll sign into your iCloud and pick your most recent back up that you did and you'll have everything on your new phone. But before starting your backup make sure that everything under your iCloud is switched on so that it has access to all of your stuff to be able to back it up.